When learning to fly an RC airplane, a new pilot may accidentally pilot the RC airplane into an unintended attitude (roll, pitch, and yaw) that may cause the RC airplane to crash. To alleviate this concern, RC airplane manufacturers have developed RC airplane training systems that attempt to reduce the likelihood of crashes caused by pilot error.
Some prior RC airplane training systems rely upon optical and/or infrared (IR) sensors that monitor the angle of the airplane relative to the horizon, and attempt return the RC airplane to a neutral position relative to the horizon, e.g, by leveling the wings with the horizon (i.e., adjusting the roll) and/or leveling the nose with the horizon (i.e., adjusting the pitch). Other prior airplane training systems rely upon off-axis gyroscopes to keep the wings and/or nose of the RC airplane to within a limited relative angular position.
However, the optical/IR sensors used in prior training systems are affected by certain flight conditions that substantially limit their effectiveness. For example, on overcast days or at dusk, it is more difficult for the optical/IR sensors to discern the horizon. Similarly, flying near reflective surfaces such as bodies of water or reflective roadways or buildings limits the ability of the optical and/or IR sensors to discern the horizon. Additionally, optical/IR sensor-based training systems are largely ineffective (if not wholly ineffective) when flying RC airplanes indoors, e.g., in gymnasiums, indoor stadiums, and other large indoor facilities.
Likewise, prior off-axis gyroscope-based training systems that rely on relative angular position measurements have no inertial knowledge, and thus, are unable to (i) estimate the inertial positioning of the RC airplane, (ii) reliably keep the RC airplane within a particular inertial envelope, or (iii) control the RC airplane to a particular inertial attitude.